The morphology of high-current electron-beam-initiated fractures in InGaN/GaN heterostructures

The morphology of fractures in InGaN/GaN heterostructures on sapphire substrates under multipulse irradiation by a high-current electron beam is experimentally investigated. It is established that excitation of samples by an electron beam with the threshold density from the heterostructure side leads to the formation of microfractures the number, size, and shape of which change during irradiation and are determined by individual properties of investigated samples. In heterostructures with stimulated luminescence, at the instant of the excitation pulse, bright microregions were detected against a background of homogeneous cathodoluminescence. The spatial positions of these microregions coincide with those of residual microfractures. Possible mechanisms of the electron-beam-initiated fracture of light-emitting heterostructures are analyzed.